LibWeb: Fix drawing axis-aligned lines

MacDue · awesomekling · commit 00b24a55b189 · 2024-01-09T00:03:09.000+01:00
Previously, these were clipped by the RecordingPainter, which used the path's bounding box (which in this case is zero width or height). The fix is to expand the bounding box by the stroke width. Fixes #22661 Note: This is unrelated to any recent LibGfx changes :^)
diff --git a/Tests/LibWeb/Ref/reference/images/svg-axis-aligned-lines-ref.png b/Tests/LibWeb/Ref/reference/images/svg-axis-aligned-lines-ref.png
diff --git a/Tests/LibWeb/Ref/reference/svg-axis-aligned-lines-ref.html b/Tests/LibWeb/Ref/reference/svg-axis-aligned-lines-ref.html
@@ -0,0 +1,9 @@
+<style>
+* {
+    margin: 0;
+}
+body {
+    background-color: white;
+}
+</style>
+<img src="./images/svg-axis-aligned-lines-ref.png">
diff --git a/Tests/LibWeb/Ref/svg-axis-aligned-lines.html b/Tests/LibWeb/Ref/svg-axis-aligned-lines.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<style>
+  body {
+    background-color: white;
+  }
+</style>
+<link rel="match" href="reference/svg-axis-aligned-lines-ref.html" />
+<svg width="100" height="100" viewBox="0 0 24 24" stroke="black" stroke-width="5">
+<line x1="12" y1="0" x2="12" y2="24"></line>
+<line x1="0" y1="12" x2="24" y2="12"></line>
+</svg>
diff --git a/Userland/Libraries/LibWeb/Painting/RecordingPainter.cpp b/Userland/Libraries/LibWeb/Painting/RecordingPainter.cpp
@@ -97,6 +97,8 @@ void RecordingPainter::stroke_path(StrokePathUsingColorParams params)
 {
     auto aa_translation = state().translation.map(params.translation.value_or(Gfx::FloatPoint {}));
     auto path_bounding_rect = params.path.bounding_box().translated(aa_translation).to_type<int>();
+    // Increase path bounding box by `thickness` to account for stroke.
+    path_bounding_rect.inflate(params.thickness, params.thickness);
     push_command(StrokePathUsingColor {
         .path_bounding_rect = path_bounding_rect,
         .path = params.path,
@@ -110,6 +112,8 @@ void RecordingPainter::stroke_path(StrokePathUsingPaintStyleParams params)
 {
     auto aa_translation = state().translation.map(params.translation.value_or(Gfx::FloatPoint {}));
     auto path_bounding_rect = params.path.bounding_box().translated(aa_translation).to_type<int>();
+    // Increase path bounding box by `thickness` to account for stroke.
+    path_bounding_rect.inflate(params.thickness, params.thickness);
     push_command(StrokePathUsingPaintStyle {
         .path_bounding_rect = path_bounding_rect,
         .path = params.path,
